ES2291388T3 - DESPENSATION SYSTEM. - Google Patents

Abstract

A product dispensing system comprises a calibrated nebulizer having a nebulizer jet, mouthpiece, means for sourcing compressed air, a manifold for distributing the source of compressed air in at least one direction, a nebulizer accommodation means which is accessed by port, and a valve means for controlling the manifold and thereby the flow of compressed air to the port. The manifold and the port are linked by a length of tube, wherein the internal volume of the tube from the manifold outlet to the nebulizer jet is less than 0.7ml. <IMAGE>

Description

Dispensing system

This invention relates to a system of dispensing, in particular to one that can be used, for example,  in dispensing small amounts of medication, when it is It is necessary to dispense it in aerosol form.

It is known to include a measurement system for Dosing systems that provide a nebulized substance. For example, GB 1,568,808, (Rosenthal) describes a measurement system to deliver a nebulized substance for inhalation by a patient comprising means of nebulization, detection means to detect the onset of patient inhalation, adjustable timing means for set a timed operation, and controlled valve means by the timing means, in order to provide a controlled dosage of nebulized substance.

The preamble of claim 1 is based in the description of this document.

However, for this system to work and provide an accurate dose of medication, it is necessary that the system use a calibrated nebulizer that has a flow rate of precise output with respect to time. Nebulizers available in the market have a wide variety of outputs with Regarding time. In addition, the calibration must remain constant as the nebulizer is used, and the nebulizer must be connected to the dosing device in such a way that the Nebulizer calibration is valid and recognized when done work with the dispensing device. This is particularly important in relation to the length of the tube between the valve and the nebulizer.

It is also noted that this request does not describes any teaching of a device that is not of any calibrated manner for use with a proposed drug. This can due to the fact that the device materialized in this request is designed for provocation tests, which They are usually carried out in a laboratory, and used to deliver aerosol pulses to the airway of a patient with in order to determine their reactivity to allergens. The device does not It has been designed for the patient to take home, and to administer precise doses of medication daily.

In addition to the previous request, the GB document 2,164,569 (Etela-Hameen Kauhkovammayhdiatys RY (Finland)) describes a system similar to the one described above, which has also been designed for provocation tests, except because it has an additional control of the start time of the atomization, which is used to select the start time of the atomization to match the beginning of the phase of inspiration, which has been ascertained by exam that is favorable For a particular patient.

EP 519,742 (DeVillbis Healthcare Inc) describes a control system of a medical nebulizer that It has a three way valve. In the embodiment, a part of the valve is connected to a pressure sensor, and another is connected to a compressed air supply. Control system inside this apparatus use the supply tube to the nebulizer to detect the patient's breathing pattern. When it detects inhalation, switch the valve to the compressed air supply, which then operates the nebulizer for a period of time default, regardless of whether the patient has continued inhaling or not. This device also presents the problems of other nebulizers because there is a long tube length between the control box and nebulizer. In addition the nebulizer can be supplied by any manufacturer, and therefore its calibration is not attached to the device, thereby causing it to distribute varying amounts of medication.

According to the present invention, a product dispensing system comprising a nebulizer calibrated that has a nebulizer injector, a nozzle, means to generate compressed air, a distributor to distribute the compressed air in at least one direction, an opening, and means of valve to control the distributor and therefore the air flow compressed to the opening, the distributor and the opening being joined by a length of tube, characterized by means of nebulizer housing accessed through the opening, by a sensor to detect a patient's breathing to indicate the patient's inhalation flow rate and by means to determine the distributed dose, the dose determined based on the outflow of the medication from the nebulizer, and the duration of the administration of the medication, serving the means of dose determination to adjust the output flow value used to calculate the dose based on the flow rate of patient inhalation detected by the sensor.

Preferably, the internal volume of the tube from the distributor outlet to the nebulizer injector is less than 0.5 ml.

Conveniently, the dispensing system according to the invention it is used together with a small compressor  of air as the source of compressed air, which has a flow rate of flow in the area of 1 to 2 liters per minute.

"Calibrated" is understood in this case. that the dosing flow for the nebulizer has already been established, and the dosimeter programmed accordingly, to thus provide a known dosage flow rate for a given medication It is anticipated that a given dosimeter will have one or more dedicated nebulizers

In preferred embodiments of the invention, the dispensing system additionally comprises means of switch, which are sensitive as to whether air is flowing compressed in the system.

It is another preferred aspect of the invention that may comprise a dispensing system comprising a dosimeter that has been previously programmed to dose one or more medications according to predetermined dosage profiles.

The dispensing system according to the invention is conveniently one that can be pre-programmed to dose one or more different types of drugs, which can be It is necessary to dose according to different profiles. Will be familiar for those skilled in the art methods for preprogramming the dispensing system in such a way. In addition, the nebulizer and the dosimeter according to the invention is calibrated to determine the dosage of a drug as described in EP document 587,380 (Medic-Aid Limited), whose contents are Incorporate this document as a reference.

The dispensing system according to the invention incorporates a nebulizer and a mouthpiece, for which the medication nebulized can really be administered to the patient. System dispensing also additionally comprises a pressure sensor, which can in operation detect a pressure drop in the apparatus in response to the patient's breathing, and to then deliver a pulse of nebulized medication to the nozzle. In such cases, the dose of medication can be calculated by the known output flow rate with respect to the time for selected drug, and the sum of all nebulizer pulses that has managed the system, in known ways for experts in the art, as mentioned above. Such ways may normally include conducting clinical trials of the drug to determine appropriate dosages, and schedule them electronically in the dispensing system.

It will be understood that the distributor in an apparatus of dispensing according to the invention may, in fact, be a part solidarity of the valve means, and it does not need to be a discrete entity separately. In certain embodiments, the distributor is a block configured with internal galleries, by example, made of plastic materials, and their presence allows to the pipes connect to the openings in the valve. Openings on the valve can be very close to each other to accommodate the pipe connection directly, and a distributor increases the space between them; in other embodiments it may be necessary that the distributor distributes compressed air in at least two different addresses

The dispensing system according to the invention It can work from a variety of different sources of compressed air, such as a continuous air supply to a flow rate of about 6 liters per minute. This one can usually be provided well from a pressurized cylinder such as used in hospitals, or it can be generated from a compressor of conventional air.

In an alternative and preferred configuration, the dispensing system can be operated with a system of Lightweight compressor, which typically generates a low flow rate (in the order of 1 to 2 liters per minute, preferably 1.5 liters per minute), together with an accumulator. A combination of this type of a low flow flow compressor and an accumulator allows the dispensing system to produce air pulses compressed to a nebulizer in the dispensing system with the flow approximately 6 liters per minute, in which the flow since the compressor is matched with the average flow through the nebulizer (1.5 liters per minute). In addition, such a combination of a low flow flow compressor with accumulator, together with the dispensing system according to the invention provides a Dosing device that is lighter, compact and easy to transport than known dosing devices.

With respect to the distributor, if the device of dispensing according to the invention is used in conjunction with a low flow flow compressor, it is only necessary that the valve connect and disconnect compressed air to the nebulizer, in whose case the distributor may only need to direct the compressed air Only in one direction. However, if the dispensing system it is used in conjunction with a conventional air supply such as a compressor or supply per six-liter gas bottle per minute, the distributor together with the valve directs the flow either to the nebulizer or to the outlet hole. In such circumstances, the valve together with the distributor has either one opening or two exit openings, depending on the application.

An important feature of the systems of dispensing according to the invention is in the volume of the connecting tube the distributor and the opening that is less than 0.7 ml, preferably less than 0.5 ml. It has been discovered that using tube lengths that have a relatively small volume, the nebulizer starts working as quickly as possible once that the patient's inhalation has been detected. Normally it is it is possible that the nebulizer can work within 50 milliseconds after detecting patient inhalation. For facilitate both the fast response time and the low volume of the tube that joins the distributor and the opening, it is preferred that the valve is physically close to the nebulizer.

If a relatively long tube is used, or one with a large internal volume between the distributor and the nebulizer, this tube has to be pressurized before the Nebulizer start working. This may have effects. significant in system performance with respect to control of the output flow of the nebulizer, since the nebulizer should preferably having an essentially constant flow ("square wave") of pressure over time, so that its output is constant over time. The nebulizer used in the dispensing system is preferably one that delivers inspirational patterns lasting between 0.1 and 1.5 seconds.

The invention will now be described further. by way of example only with reference to the attached drawings, in the that:

Figure 1 shows a schematic view of a dispensing system according to the invention, complete equipped with a nebulizer and a mouthpiece;

Figure 2 shows a sectional view schematic transverse end of nebulizer / nozzle dispensing system of figure 1;

Figure 3 shows a sectional view additional schematic transverse end of nebulizer / nozzle of the dispensing system of Figure 1 from an orthogonal position to that shown in figure 2;

Figure 4 shows a sectional view schematic transverse of the control system end of the dispensing system of figure 1;

Figure 5 shows a schematic view of the dispensing system of figure 1 coupled to a compressor of low flow rate;

Figure 6 shows a representation schematic of the dispensing system / compressor system combined of figure 5;

Figure 7 shows a loading regime for load an embodiment of the dispensing system according to one aspect of the invention; Y

Figure 8 shows a cleaning regime for cleaning an embodiment of the dispensing system according to a aspect of the invention.

Figure 9 shows an accumulator consisting in a generally hemispherical elastic diaphragm.

Figure 10 is a graph showing the flow rate output of a conventional nebulizer with respect to the flow of patient inspiration.

With reference to the figures, an embodiment of the dispensing system according to the invention comprises a hand dosimeter having a height of approximately 200 mm and a weight of approximately 200 g. The dosimeter has a mouthpiece (1) and a nebulizer (2) coupled, and a body (3) containing a control valve, electronic circuitry and a drums. These components can be accessed through the base (4).

The dosimeter is connected to an air source compressed through a tube (10). To operate the dosimeter, the patient removes the mouthpiece (1), and pours a form liquid of the medicine (which can be a liquid or a powder in fluid form, or any other similar form) inside the nebulizer (2). Then the dosimeter connects to the air supply compressed through the tube (10). By means of a device switch that will be described later, the presence of a positive pressure in the dosimeter activates the circuitry of control on the dosimeter, and turn it on.

In this embodiment, although the nebulizer has only one accommodation in which the medicine is placed, the dosimeter however is previously programmed to administer the correct dose of two different proposed drugs. Dosimeter it could, however, be built and pre-programmed to administer a desired number of proposed drugs. The drug that has been loaded in the nebulizer is selected using buttons  (5) and (6) selector. Once the type of drug, LEDs (7) and (8) indicate the type of drug selected by the patient Button (9) is a reset button, so that the User can correct any errors in the selection.

The nebulizer used in the system dispensing according to the invention can be any design of suitable nebulizer with a known calibration constant that It is used to nebulize substances such as medications, which is properly adapted to fit the system dispensing, and calibrated with the dosimeter. Suitable nebulizers include those that use a source of compressed air to nebulize the medicine, and are described, for example, in the European patent number 672,266 (Medic-Aid Limited), whose contents are incorporated as a reference.

When the drug has been selected, the patient inspires through the mouthpiece (1). A pressure sensor (which will be described further below) inside the body (3) detects a pressure drop inside the nozzle (1) due to patient inhalation, and then delivers a pulse pre-programmed nebulized medication in the first 50% of the inspiration profile, until the scheduled dose regimen in the dispensing system it has been administered.

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The dose is calculated from a known output flow rate with respect to the time for the selected drug, and the sum of all nebulizer pulses that the dosimeter has administered. Additional information about how dosages of drug can be derived and programmed in advance can be obtained from GB 2,294,402 (Medic-Aid Limited et al ), the contents of which are incorporated herein by reference. In this case, clinical trials have been carried out to determine the dose of drug that should be administered to achieve the desired therapeutic effect, and this dose has been programmed in the dosimeter for the two proposed drugs.

When the scheduled dose has been administered, the LED adjacent to the button relative to the selected drug flashes quickly and a buzzer sounds, indicating that the treatment has completed, and thereby ensuring that a precise dose of drug is administered to the patient on each occasion.

The nebulizer used in this embodiment is shown in more detail in figures 2 and 3. Air is supplied compressed through the opening (17) to the injector (11) of nebulizer, and this works in conjunction with the deflector (12) to form a spray of the liquid drug that has been placed in the container (19) of the nebulizer.

This nebulizer is a venturi nebulizer that sucks air through the spigot (13) towards the center of the baffle (12), and then up and out through from the spout outlet (13) towards the nozzle. As the nebulizer only generates spray during inspiration, the air inhaled by patients is aspirated through the valve (14), and additionally through the mouthpiece to the patient. A proportion small of this air is sucked down through the center of the nebulizer to operate the venturi system. If the flow to through the nebulizer is completely independent of the flow of the patient, the nebulizer produces a constant flow of output. The valve (14) creates a pressure drop inside the nozzle, and This is monitored through the opening (18). In the valve (14) exhalation will close, and the patient will exhale through the valve (15). EP 627,266 (Medic-Aid Limited) contains more information about the nebulizer.

The complete set remains in place through the catch (16). When the lower end of the catch is displaces the nozzle can be removed. The upper end of the sear can be tilted down to release the container assembly of nebulizer of the main housing (3) of the dosimeter. This allows the entire nebulizer unit to be removed after completed the treatment, and cleaned completely separated from the main dosimeter housing. This is further illustrated graphically. in figures 7 and 8.

Figure 4 shows an internal section through of the dosimeter, which shows in particular the configuration Device electronics The air is introduced into the dosimeter to through a tube (10) and through a flexible tube (22) to distributor (21) and forward to the valve (20). To determine if there is a pressure in the tube (22), a wall has been configured (28) circular. When there is no pressure in the tube, the tube falls. Without However, under pressure it expands, and moves the lever (29) against the switch (30), which turns on the dosimeter.

The dosimeter can be operated from several different compressed air sources; first can use either a continuous air supply of approximately 6 liters per minute, generated from an air compressor conventional, or a supply of compressed bottled gas such as It is used in hospitals. With these compressed air sources, when the compressed air is not being supplied to the nebulizer to through the tube (23) and the opening (17), it must be evacuated externally through the tube (24) out of the dosimeter base through a hole that matches the size of the injector diameter (11) in the nebulizer. This maintains a constant pressure on the system regardless of whether the valve is directing air to the nebulizer or ventilation duct.

In an alternative and preferred embodiment, which can be used in conjunction with other dosimeter forms, the dosimeter can be operated in conjunction with a system of low flow rate compressor having a flow rate of 1 at 2 liters per minute, which is has a built-in accumulator.

This compressor system generates a low flow of, for example, 1.5 liters per minute in the accumulator, and this allows the dosimeter to produce pulses of compressed air by nebulizer with an equivalent flow rate of approximately 6 liters per minute, in which the flow from the compressor is made match the average flow through the nebulizer (1.5 liters per minute). In this configuration the tube (24) is sealed, and when the valve (20) is closed, the pressure in the tube (10) of supply is diverted to the compressor accumulator. The opening (18) connect the pressure sensor (25) to the nozzle. This one is coupled to the printed circuit board (31) that is powered per battery (26). When the electronic system detects that the patient has inhaled, the valve (20) deflects the pressure flow towards the tube (23) and out to a nebulizer through the opening (17). The battery is inserted into the dosimeter through the door (27) at the base (4).

An example of a flow rate compressor suitable under that can be used as described shown above in figures 5 and 6, and comprises a Small air compressor with a flow of approximately 1.5 liters per minute, and an accumulator with a volume of approximately 0.2 liters, which can be formed, for example, in the tube system between the compressor and the dosimeter, or using an arrangement of Bellows and springs inside the compressor housing. TO a rubber hemisphere accumulator is described below that It works particularly well. The compressor works until the accumulator has reached its capacity, and then it shuts down. He dosimeter receives pulses of air from the accumulator until the accumulator has been emptied to a specified volume (0.1 liters) The compressor then stops and refills the accumulator. The compressor produces an average output flow rate that is known for the dosimeter, and the dosimeter controls your supply of air so that it does not exceed the average flow rate from the compressor, and any pulse delivered by the dosimeter not exceeds the capacity of the accumulator. This system therefore uses the compressor, which is about a quarter the size of a conventional compressor system, and a quarter of the requirement of Energy. A compressor of this type is also cheaper to manufacture to proportionate.

The accumulator in this embodiment should have a relationship between pressure and linear volume during a period of an administration of a pulse, which usually has a duration 1.5 seconds, with a nebulizer injector flow of 6 liters per minute, the accumulator should provide a flow of 150 milliliter volume at a constant pressure (lbar +/- 10%). It is difficult to obtain a regular linear relationship between pressure and volume. Figure 9 shows a hemispherical rubber accumulator natural. The rubber has a linear elongation load between a elongation of 100% and 500%. A diaphragm 91 is a component hemispherical that remains trapped between two rings 92 and 93. In Figure 9, the diaphragm is shown in three positions marked A, B, C. Position A is the unloaded position from which it begins the diaphragm and as compressed air is supplied through of an opening 94, the diaphragm expands to position C with a 200% elongation. The compressed air supply stops then well for the action of a microswitch on the diaphragm surface (not shown) that stops the compressors, or by a pneumatic microswitch that then evacuates the compressor output Diaphragm 91 then remains in this position until the valve sends an air pulse to the nebulizer When the diaphragm delivers air, the pressure drop during operation it is less than 5%. The diaphragm can supply air at a stable pressure until it reaches the position B which is an elongation of 120%. The microswitch I would then restart the compressor, or the microswitch tire would close. This hemispherical arrangement is relatively simple to manufacture, but it has great advantages over other accumulator systems that could be used.

A configuration is shown in Figure 6 electric suitable for a compressor of this type.

So that the dispensing system according to the invention work effectively, the dosimeter valve (20) should be near the nebulizer, so when the system detects the patient's inhalation, the nebulizer begins to run as quickly as possible, usually in less than 50 milliseconds This means that the length of the tube (23) between the distributor outlet and the nebulizer injector must be short, with an internal volume of less than 0.7 ml, preferably less than 0.5 ml, which represents 5% of the pulse shorter than Deliver the nebulizer. If a long tube is used between the valve and the nebulizer, this tube has to be pressurized before the Nebulizer start working. This significantly affects the system performance, in terms of output flow control of the nebulizer must be supplied with a "square wave" of air pressure, so that the output is constant along the time, and delivered at the beginning of inhalation. The nebulizer delivers pulses to inspiration patterns lasting between 0.1 and 1.5 seconds.

One of the simplest ways to determine the dose of medication that the patient receives is, as described previously, multiply the output flow of the nebulizer by The duration of each pulse. The doses are then determined by adding the amount of medication that is received during each pulse. This calculation is based on the fact that the output flow of a nebulizer should be constant regardless of the flow rate of patient inhalation Therefore, provided the outflow of the nebulizer be the same for a person who inhales slowly that for a patient who inhales quickly, the calculation will be precise. If the output flow of the nebulizer varies with the Inhalation rate, the accuracy of the dosimeter will vary.

Figure 10 is a graph showing the variation of aerosol outlet flow rate with flow rate  of inspiration for a conventional nebulizer. As you will see, the output is not constant.

Therefore it is proposed to use the sensor pressure to provide information on the flow rate of the patient so that the correct flow rate of the Nebulizer is determined during patient inhalation. This it can be done in the form of a query table that is quite effective, and the query table can have two or more calibration points as required to provide the precision needed A satisfactory query table can achieved using an approximation of the query table which, in the case of the graph shown in figure 10, can be created at from two straight lines, a line that generally follows the curve to the point of 30 bpm and a second line that generally follows the upper curve to this one. Such an approach works well because, in actually, a patient's breathing pattern is not in a fixed level, but it is constantly changing.

Another way to use the calibration value correct is to use the computer that takes into account the flow of inspiration flow. A calibration value can be used. above the level of 30 liters per minute, and when the flow is approximately less than 15 liters per minute, then the Constant calibration is reduced to 60% of that value. By therefore, the calculation can be achieved in several different ways not only through a multi-point query table.

Claims (25)

1. Product dispensing system comprising a calibrated nebulizer (2) having a nebulizer injector (11), a nozzle (1), means (10, 22) for generating compressed air, a distributor (21) for distributing the compressed air in at least one direction, an opening (17), and valve means (20) for controlling the distributor (21) and therefore the flow of compressed air to the opening (17), the distributor (21) being and the opening (17) connected by a tube length (23), characterized by nebulizer housing means accessed through the opening (19), by a sensor to detect the breathing of a patient to indicate the inhalation flow rate of the patient and by means to determine the dispensed dose, the dose determined based on the outflow of the medication from the nebulizer (21), and the duration of the administration of the medication, serving the means of determining the dose to adjust the value of the output flow u Used to calculate the dose based on the patient's inhalation rate detected by the sensor. 2. System according to claim 1, wherein the internal volume of the tube from the distributor outlet to The nebulizer injector is less than 0.7 ml. 3. Dispensing system according to claim 1 or claim 2, previously programmed for dose one or more medications according to dosage profiles default 4. Dispensing system according to any one of claims 1 to 3, wherein the distributor is solidarity with the valve means. 5. Dispensing system according to any one of the preceding claims, wherein the sensor for detecting a patient's breathing is a pressure sensor to detect a drop in pressure in the device in response to the breathing of a patient to indicate the inhalation flow rate of the patient. 6. Dispensing system according to any one of the preceding claims, further comprising a compressor that has a flow rate of 1 to 2 liters per minute and an accumulator 7. Dispensing system according to any one of claims 1 to 6, further comprising means of switch that are sensitive as to whether air is flowing compressed in the system. 8. Dispensing system according to any one of the preceding claims, wherein the distributor is a block configured with integrated galleries whose presence allows that the tubes connect to the openings in the valve. 9. Dispensing system according to any one of claims 1 to 5, further comprising a compressor and an accumulator 10. Dispensing system according to claim 9, further comprising a compressor system Lightweight and an accumulator. 11. Dispensing system according to claim 10, wherein the light compressor generates a flow rate of  low flow of the order of 1 to 2 liters per minute. 12. Dispensing system according to claim 10 to 11, wherein the combination of the compressor and the accumulator allows the dispensing system to produce pulses of compressed air to the nebulizer with a flow of approximately 6 liters per minute 13. Dispensing system according to any one of claims 9 to 12, wherein the valve means They are used to connect and disconnect compressed air. 14. Dispensing system according to any one of claims 9 to 13, wherein the accumulator includes a flexible elastic body that has a relationship between pressure and generally linear volume. 15. Dispensing system according to claim 14, wherein the flexible body is an element Flexible usually hemispherical. 16. Dispensing system according to claim 15, wherein the hemispherical element is a Extensible diaphragm up to 500% of its volume discharged. 17. Dispensing system according to any one of the preceding claims, wherein the distributor together with the valve means serve to direct the air flow compressed either to the nebulizer or to an outlet hole. 18. Dispensing system according to any one of the preceding claims, wherein the volume of the tube that links the outlet of the distributor to the nebulizer injector is less than 0.5 ml. 19. Dispensing system according to any one of the preceding claims wherein the nebulizer serves to deliver inspiration pulses lasting between 0.1 and 1.5 seconds. 20. Dispensing system according to any one of the preceding claims, further comprising means to calculate the medication dosage based on the flow rate known out of medication regarding the time for the selected drug. 21. System according to any one of the previous claims, further comprising an indicator for indicate when the necessary dose of the product. 22. System according to any one of the previous claims, wherein the means of determination of the dose include a consultation table through which the flow rate output used when calculating the dose is based on the flow rate of patient inhalation 23. System according to claim 22, in the that the query table includes two or more points of calibration. 24. System according to any one of the claims 1 to 21, wherein the means for determining the dose includes a computer ready to use a first calibration value greater than 30 liters per minute of flow in inhalation, and a second calibration point when the flow rate is less than 15 liters per minute. 25. System according to claim 24, in the that the second calibration point is 60% of the first.